It has been known that certain animal, reptile and fowl excrement contain various nitrogenous materials, a significant portion of which may be found as uric acid. Uric acid has the empirical formula C.sub.5 H.sub.4 N.sub.4 O.sub.3. The structural formula is: ##STR1## A major source of uric acid in the past has been marine bird guano obtained primarily in the Galapagos Islands. A process has been described in U.S. Pat. No. 2,302,204 for obtaining uric acid from bird guano. The process described therein involves numerous dissolution and precipitation steps, many of which are carried out at elevated temperatures in a highly alkaline media which is known to degrade uric acid. The complexity of this process, as well as the product loss which is caused by conditions under which it is carried out, leave much room for improvement. On the other hand, improvements described herein disclose steps in which the raw material is promptly collected, dried, ground and sieved. These preliminary steps constitute an improvement which involves very few steps but yet results in the beneficiation of a very pure, high concentration or product in very high yields.
Disadvantages in the prior art overcome by the practice of the novel process of the present invention, which yields a substantially pure or pure (chemical and pharmaceutical grade) uric acid (in extremely high yields) which is characterized by exhibiting an improved color, i.e., is essentially colorless or white, has an extremely low concentration of impurities, and is prepared in a convenient, economical and efficient manner. In accordance, then, with the present invention, it has been found possible to prepare pure (chemical and pharmaceutical grade) uric acid, in very high yields, having the aforementioned characteristics, which has heretofore not been obtainable by prior art processes on a large scale. Additionally, the process as described herein is adaptable to obtaining substantially pure primary salts of uric acid having the empirical formula of MHC.sub.5 H.sub.2 N.sub.4 O.sub.3 in which "M" is an alkali earth metal.
Uric acid is known in the art to have a significant value as a chemical compound and consequently, has a wide variety of uses. Uric acid, for example, can be used for the commercial production of allantoin, alloxan, alloxantin, parabanic acid, murexide and other derivatives. Uric acid and its salts, for example, have been and are still being used on occasion in medicine. It has been used internally for edematous heart, pulmonary tuberculosis, persecution mania, et cetera, and also externally in gout. A 4% ointment of ammonium urate has been used in the treatment of chronic eczema and also internally for coughs and grippe. Lithium acid urate is used as an antarthritic, and murexide is used as an organic indicator for the determination of calcium and other metal ions.
The beneficiation method disclosed herein is particularly adaptable to utilization of waste material obtained from large commercial bird establishments such as turkey and chicken farms. Thus, in addition to providing a method for obtaining a valuable raw material such as uric acid and its primary salts, the process provides a solution for serious disposal problems and for obtaining a valuable animal feed and supplement.